Blending the image
Painting with layers enable you to work on elements without compromising the entire image, but generating too many layers featuring lone elements can be overwhelming and slow you down. So there’ll come a time when you can either choose to collapse your stack, reduce the number of layers and paint over everything, or you can continue to work with separate layers. I recommend picking some values and colours from the background and painting over your layers with a soft airbrush on a very low Opacity. This will affect the local colour and simulate a fog that brings colours together. It’s also good to redefine the edges of your shapes and elements, so that the light is cohesive and blended correctly.